test: remove plugin-vue from tailwind playground

[sapphi-red]

Description

Remove plugin-vue from tailwind playground.

• Migrate tailwind + vue + pug test (fix(plugin-vue): trigger css hmr on custom template languages #6987) to plugin-vue repo: test: migrate tailwind + pug test from Vite repo vite-plugin-vue#224
• Rewrite duplicate entry in moduleGraph test (fix: call createFileOnlyEntry() only for CSS deps, fix #4150 #4267)
  • The previous test was checking whether the updated style will be applied. The new test checks whether a full reload will happen. (If there isn't a duplicate entry, a full reload doesn't happen.) It's quite difficult to replicate the previous complete behavior as it depends on how the plugin handles HMR. I think the new one still covers the original bug.
  • I checked that this new test doesn't pass if I revert the changes in fix: call createFileOnlyEntry() only for CSS deps, fix #4150 #4267.
• Rewrite postcss dependency normalize test (fix: normalize postcss dependency messages #6959)
  • Note that the previous test passes even if I revert the changes in fix: normalize postcss dependency messages #6959. I guess it's handled somewhere else as well.

close #11175

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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